Summary

For the past 4 years, planetary scientists have wrestled over where to send NASA's next Mars rover, a $2.5 billion machine to be launched in 2020 that will collect rock samples for eventual return to Earth. This month, nearly 200 Mars scientists will gather for a final landing site workshop, where they will debate the merits of the three candidate sites that rose to the top of previous discussions, representing three aspects of martian geology that may have once been hospitable to life: a fossilized delta and lake (Jezero), a former mineral spring (Northeast Syrtis), and former hot springs (Columbia Hills). But new to this discussion is a fourth landing site, found between Jezero and Northeast Syrtis, with geology similar to the latter; the site could allow the rover to attempt an ambitious campaign, landing at one site and then traveling to sample wholly different geology. Following a vote by scientists and then internal discussions from the Mars 2020 team, NASA should finalize its plan in the next few months.